1. Field of Invention
This invention relates to a system and a method for achieving efficient combustion of hydrocarbon fuels in internal combustion engines to enhance the engine performance with reduced fuel consumption and emissions comprising at least an infrared radiation source emitting infrared at wavelengths covering at least a portion of 3-20 micrometers wavelength range so that the hydrocarbon fuel can be excited with infrared at said wavelengths before entering engine chamber for combustion and a hydrogen source providing hydrogen gas to be burned along with the infrared-excited hydrocarbon fuel in engine cylinder. The hydrocarbon fuel can be any of gaseous or liquid fuels, such as methane, propane, gasoline, ethanol, diesels, biodiesels, and renewable fuels that are used to power internal combustion engines.
2. Description of Prior Art
In Organic Chemistry photoexciting hydrocarbons with infrared photons shorter than 20 μm (micrometers) in wavelengths for improving fuel conversion efficiency is scientifically predicted. When a photon is absorbed by a molecule, it ceases to exist and its energy is transferred to the molecule in one of vibrational, rotational, electronic, and translational forms. Hydrocarbon molecules are known to be infrared-active and absorb infrared photons in 3-20 μm wavelengths to cause molecular vibrations in stretching and/or bending movement.
After years of research the present inventor discovered the use of infrared radiation at 3-20 μm wavelengths, defined as “mid-infrared” by U.S. NASA but “far infrared” in Japanese convention, for enhancing combustion efficiency of hydrocarbon fuels in internal combustion engines and resulted in the inventions of fuel combustion enhancement devices as disclosed in the U.S. Pat. Nos. 6,026,788, 6,082,339 and 7,617,815.
The present inventor has proven the underlining science of infrared-excitation effect on fuel in a laminar non-premixed counterflow methane-air flame experimentation at Purdue University (West Lafayette, Ind., USA) to help pinpoint the IR-excitation influence on combustion of hydrocarbon fuels. The present inventor further verified in separate engine and vehicle tests that infrared excitation at said wavelengths does help improve engine performance with significant reduction in both fuel consumption and emissions.
Though the device as described in the U.S. Pat. Nos. 6,026,788, 6,082,339 and 7,617,815 by the present inventor worked adequately for both gasoline and diesel engines, the fuel excitation effect became limited in the applications of heavy heavy-duty diesel engines, such as in earth moving equipment, marine vessels, locomotives, or power generators. These applications require irradiating an extensive flow of fuel substance in a very short time interval. In particular, some applications at the extreme end of the spectrum may require the use of heavy oils (e.g. #6 diesels, bunker oils) and to operate at very low engine speeds (e.g. 100 RPM's). These applications impose a limitation upon the efficacy of infrared excitation and raises a challenge to the current infrared-fuel technology.
On the other front, hydrogen (H2) has been considered as an alternate fuel or as an additional fuel to accompany fossil fuels in internal combustion engines, as described in the U.S. Pat. Nos. 5,139,002, 6,655,324, 6,779,337, 6,845,608, 7,290,504, and 7,721,682, for the benefits of reduced engine emissions. There are several advantages of hydrogen for the purported applications, including hydrogen has high speed of flame propagation and it increases the H/C ratio of the entire fuel, just to name a few. Faster combustion of hydrogen fuel or hydrogen-blended conventional fossil fuels in engine becomes closer to constant volume causing an increase of the indicated efficiency, and thus reducing fuel consumption and carbon emissions. Of course, there are also numerous problems associated with hydrogen bi-fuel technology, such as uncontrollable hydrogen self-ignition, intensive combustion knock, and instability of combustion that limit the wide spread of hydrogen technologies.
During the development of IR-fuel technology, the present inventor had realized a collective benefit on the combined use of IR-excitation and hydrogen-addition in the combustion of hydrocarbon fuels for improved fuel efficiency in internal combustion engines, which had not been taught by any of prior arts.
In Quantum Mechanics, the reaction (oxidation) rate W is determined by Arrhenius equation:W=Rke−E/RT where k is a constant, R the universal gas constant, T temperature in Kelvin ° K, and E the activation energy required to overcome the activation barrier.
It was recognized early in the study of chemical kinetics that increasing the energy of reactants increased reaction rate W, and it was usually accomplished by simply raising the reaction temperature T. However, in 1930's Evans and Polanyi illustrated the importance of molecular vibrational energy in reaction dynamics and claimed the reactant vibrational energy is the most effective at promoting reaction. Their expectation was that if the vibrational excitations were sufficient to lower the activation barrier of reactants E, substantial rate enhancement would be realized.
Based on Arrhenius equation, it becomes comprehensible why increased reaction rate W was usually accomplished by raising the reaction temperature T in early study of chemical kinetics. It made perfect sense in that time because W increases when T increases. However, it was Evans and Polanyi who discovered an alternate for increased W with a reduced E and suggested increasing reactant vibrational energy would be the most effective means to promote reaction, which can be accomplished by the infrared-excitation effect introduced by the present inventor.
The factor (E/T) can be used as a simple indicator to predict the reaction rate W during combustion. A smaller (E/T) will be always desirable for a higher reaction rate W. As mentioned above, hydrogen has high speed of flame propagation that can increase local temperature T around the flame front in spark ignition (SI) engines or around the diesel fuel spray in compression ignition (CI) engines, while IR-excitation can lower the activation barrier E of hydrocarbon fuels, which makes perfect match for a smaller (E/T) as desired.
In summary, in the aforementioned laminar non-premixed counterflow methane-air flame experimentation the present inventor has proved that the IR-excited hydrocarbon fuels combust faster than regular hydrocarbon fuels, while the existing problems associated with the hydrogen-blended hydrocarbon fuel is on the fact that hydrogen burns faster than conventional hydrocarbon fuels. As such, the addition of IR-excitation effect to current hydrogen bi-fuel technology can decrease heterogeneity of the hydrogen-enriched hydrocarbon combustion. Better homogeneity of the combustible mixture would provide better conditions for the complete combustion process that alleviate aforementioned problems associated with hydrogen bi-fuel technology
As described above, the prior art failed to teach the combined use of IR-excitation and hydrogen enriched hydrocarbon combustion in internal combustion engines to improve the engine performance for increased power, reduced fuel consumption, and decreased emissions.